Fabrication of plaster board



Aug. 24 1926. 1,597,623

J. E. SCHUMACHER FABRICATION 0F PLASTER BOARD Filed Dec. 24, 1924 3 Sheets-Sheet 1 IN V EN TOR.

Jdf M [ii/M740? 1 BY WMWW ZLQ A TTORNE vs.

Aug. 24 1926. 1,597,623

J. E. SCHUMACHER FABRICATION OF PLASTER BOARD Filed Dec. 24 1934 s Sheets-Sheet 2 INVEN TOR.

A TTORNEYS.

Aug, 24 1926.

J. E. SCHUMACHER FABRICATION 0F PLASTER BOARD Filed Dec. 24, 3 Sheets-Sheet 3 mm m ww B 3 Patented Aug. 24, 1926.

UNITED STATES.

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' Application ma December 24, 1924. Serial No. 757,929.

This invention relates to fabrication of els in proper alignment. With squared raw edge board having a body of the r'dinary calcined gypsum, or aggregate and water, the plaster at the dges, in many instances, does not maintain the desired smoothness and shape so that it is found advantageous to finish the board by trimming the edges. This results in wasting of material and the addition of a step in the operation of man-.

ufacture, which detracts from economy of manufacture and ultimate capacity of the' manufacturing plant.

The objects ofthe present invention are first, to provide an economical, speedy method, whereby a finished rawedge boardis obtained which requires no trimming and is of such a character that panels thereof will fit against one another to form smooth joints; second, to provide a method of forming a board having hardened edge margins;

the material for the margins being introduced after the body of the board has been formed; and third, to provide a board having raw rabbeted edges. I

i These objects together with other objects and corresponding accomplishments are ob-l.

tained by means of the embodiment of my invention illustrated in the accompanying drawings, in which: i

of amachine for carrying out steps of this process; Fig. 2 is a plan view; Fig. 3 is a.

section on an enlarged scale showing a fraginent of the trimming mechanismv as seen on the line 33 of Fig. 1; Fig. 4 is a section as seen on the line 4-4 of Fig. 3; Fig;

5' is a plan view of the mechanism shown in Figs. 3 and 4; Fig. 6 is a section on an enlarged scale of a fragment of the machine showing a folder as seen on the line 6-6.

of Fig. 2; Fig. 7 is a-plan view of the structure shown in Fig. 6; Fig. 8 is a section as seen on'the line 8-8 of Fig. 6; Fig. 9 is a section asseen on .the line 99 of Fig. 6; Fig. 10 is a section as seen on the line 10-10 More particularly, the

Fig. 1 is a side elevation of a fragment of Fig. l on an enlarged scale showing the edge forming mechanism; Fig.111 is a plan view of the structure shown in Fig.10; and Fig. 12 is. a finished board.

In this art it is customary to make las ter board continuously on a machine w ich continuously advances top and bottom cover sheets, depositing the plastic material between the sheets, advancing the board so formed upon a conveyor, severing the advancing" board into panels, removing the panels from the conveyor'and then following the usual steps to produce thefinished board. A machine for carrying out-this method and the additional steps pertinent to the present invention is disclosed in the drawing and described herein. However, it will be understood that the method is not limited to performance by the-particular machine shown and described, such disclo-' sure being for illustrative purposes only.-

As shown inthe drawings, the machinefor carrying out this invention comprises a frame 15. Journalled upon {one end of the frame are rollers 16 and 17 over which a conveyor belt 18 is passed. The initially formed board is produced upon belt 18. Another roller 19 is shown journalled on the frame and a conveyor belt 20 passes thereover. Conveyor belt 20 advances the finally formed board, and; as noneof the steps performed after the green board has been finally formed are pertinent to the present invention, the remainder-of the machine is not shown. A suppl roll of paper 21 for the lower .covers "eet' is' rotatably mounted upon a sub-frame. A. similar supply roll 22 for; the upper cover sheet is rotatably mounted on the frame above the conveyor. Plaster mud is fed between the advancing sheets from a box 23 to which .the mud is delivered by a spout 24. The

sheets with the interposed plaster are carried between pressure rollers 25. As much of the structure as just described is well known in the art and differs therefrom only in that the length of the conveyor belt between rollers 16 and 17 is short, and the amount of mud suppliedis such as to leave an unfilled marginal portion between the edges of the sheets.

Mounted upon the side bars of the frame are brackets 26, These brackets-have upper ways in which are slidablymounted perspective view showing the w thickness of the plaster coreand serving as a support for the cover sheets indicated by 34 and 35 while the latter are being trimmed. .Kerfs 36 and 37 are formed on the upper and lower sides of blocks 33 for the knives 30 and 32 to enter. Knives 30 are spaced so as to trim the upper cover sheet to provide a width exactly equal to the final width of the board without further trimming and knives 32 are similarly spaced. /L

.Folders "38 are arranged at the sides of the frame to lift the marginal edges of the upper sheet 34 preparatory to the introduction of the edge material. This may be a portion of a similar plastic mass as the body mixed with a colloidal body that has the property of toughening the gypsum when set, so that the edge material will stand more abuse during manufacture and after completion of the product. It may be of material having any'desired quality. The edge material may be introduced through courses 39 which are fed from any suitable source of supply. Enough of the edge plastic mass is introduced on one edge of the board so that when the sheets .are brought back into proper position, some of the plastic material will exude. This rovides for the tongue portion of the rahbeted edge which is next formed.

The wet plaster board next passes to the edge forming mechanism. Brackets 40 on opposite sides of the frame have journalled thereon upper-and lower forming rollers indicated by 41 and 42. These rollers are for smoothing the cover sheets and for maintaining the board at its proper thickness.

Mounted 'in the bracket 40 upon vertical .the edges of the board, as

shafts are the edge formers 43 and 44. These formers are disks which roll against best shown in Figs, 10 and 11. Disk 43 has a tongue on its edgeto form a groove in the board. The disk 44 has a corresponding. groove to form a tongue of raw plasten;

Fromthe forming mechanism, the finished green board passes upon the conveyor elt 20 and is .handled in the usual manner. There is a space between conveyor belts 18 and 20 between which the plaster board must pass. For the purpose of aiding in supporting the board in this space, plates 45 may be provided, these plates bemg formed in sections to provide the table tarded plaster, t e edge margins 47 and 48 of a hard or guick setting plaster and hav- 1' ing a rabbete raw portion. Itwill be understood that it is within the scope of my invention to provide a board of the character shown without the edge margin being of a difierent material.

lVhat I claim is 1. The method of fabricating plaster board having a body and upper and lower cover sheets, which comprises interposing a cementitious mass between the sheets so as to leave an unfilled edge margin, and then introducing another plastic mass to said edge. margin.

2. The method of fabricating plaster board having a body and upper and lower cover sheets which comprises interposing a 'cementitious mass between the sheets so as to leave an unfilled edge mar 'n, lifting the edge margin of the upper s eet, and introducing another plastic mass to fill said edge margin.

3. The method of fabricating plaster board having a body and upper and lower cover sheets, which comprises continuously advancing upper and lower cover sheets, in 'terposmg a cementitlous mass between the advancing sheetsso as to leave an unfilled' margin, liftin the edge margin of the upper sheet, an introducing another plastic mass between said edge margin so as to fill the latter.

4. The method of fabricating plaster board having a body and upper and lower cover sheets, which. comprises continuously advancing the upper and'lower sheets, interposing a cementitious mass between the advancing sheets so as to leave unfilled edge margins, trimming the edge margins of said sheets, and then introducing another plastic mass between said edge margins.

5. The method of fabricating plaster board having a body andupper and lower cover sheets which comprises continuously advancing said sheets, interposing a cementitious mass between the advancing sheets so as to leave unfilled edge margins, trimming the edge margins of said sheets, lifting the edge margins of the upper sheet, and then introducing another plastic mass between said edge margins.

6. The method of fabricating plaster board having a body and upper and lower cover sheets comprising advancing the lower cover sheet, depositing a cementitious mass upon said lower cover sheet, applying the top cover sheet'thereover so asto leave unfilled edge margins, and then introducing another plastic mass between said edge margms.

The method of fabricating plaster board having a body and upper and lower cover sheets, which comprises continuously advancing the lower cover sheet, de ositing a cementitious mass upon the ower cover sheet, applying the top cover sheet thereover, so as to leave unfilled edge margins,lifting the edge margins of the upper cover sheet, and then introducing another plastic mass between said edge margins.

8. The method of fabricating plaster board having atbody and upper and lower cover sheets, which comprises continuously advancing the lower cover sheet, depositing a cementltious mass upon the lower cover sheet, continuously applying an upper cover sheet so as to leave between said sheets unfilled edge mar s, trimming the edge margins of said s sets, and then introducing another plastic mass between said edge man glIlS.

9. The method of fabricating plaster board having a body and upper and lower coversheets which comprises continuously advancing the lower cover sheet, depositing on said lower cover sheet a. cementitious mass, continuously applying the upper cover sheet so as to leave unfilled edge margins between said sheets, trimming the edge margins of said sheets, lifting the edge margins of the upper cover sheet, and then introducing another plastic mass between said 

